I sat on the couch and started in on the mail and by the time I had it opened and sorted into shred, recycle and file, I was totally overwhelmed and couldn't move. I texted my DD to tell her what was happening and she suggested I make a list and check things off to show myself that I was getting things done.

One thing that has helped me in the past is to just try and set a time limit and stick to it no matter what. I think I posted before that when I moved, I did my unpacking in the morning before work. That way, I had no choice but to stop when it was time to get ready. It was nice because 1) it ensured that I got something done every day and 2) it ensured that I also got my life done every day.

It also sounds like you (like me) are easily distracted during a task by seeing another task needing to be done and switching over to it. Try and tell yourself to keep on the task you decided to work on, and let other things go til later. It can be really really hard but it can also get better with some practice. If you keep switching activities, it's tough to accomplish the things you set out to do.